Three segments, described below from north to south, comprise this long trail (FS 835) that stretches from Peaceful Valley to the Rainbow Lakes Road (see map), with numerous ups-and-downs. Built chiefly for ski touring and mountain biking, the route is clearly marked by blue diamonds and arrows and stays mainly in the forest where it is protected from the wind. The Forest Service is still working on this trail, so be alert for changes.

It's feasible to do a two-car, one-way hike or ski trip on any of the segments. You can also combine the Sourdough with other trails for a variety of loops. If you're using two cars and connecting with other trails, check a topo map to determine what routes have the least elevation gain.

Camp Dick Campground to Beaver Reservoir (2.3 miles, 522- foot elevation gain): The best starting point for this segment of the Sourdough Trail is just beyond the west end of the Camp Dick Campground at a small parking area. From the parking area, walk along FS Road 921 for a short distance to where the Buchanan Pass Trail crosses the road. (Buchanan Pass Trail was formerly called"Middle St. Vrain Trail," and signs with this name are still posted.) At the trail sign on the left side of the road, turn left onto the Buchanan Pass Trail, which goes gently up and down across several small stream crossings and through a lush coniferous forest. In about half a mile, just past a spur to Camp Dick, you reach the Sourdough Trail junction. Turn right and climb up to a T-junction. Twinflower (eighteenth-century botanist Linnaeus's favorite flower and somewhat uncommon on the eastern side of the Continental Divide) grows profusely along this north-facing slope. At the T-junction, the right branch goes to the north end of Beaver Reservoir, connecting to the Coney Flats Road, while the main Sourdough Trail continues to the left. Several unmarked side trails intersect the main trail, which goes up and down in a generally east to southeast direction and eventually comes to a bridge that crosses Beaver Creek. From the bridge, the trail contours around a small hill up to Beaver Reservoir Road.

In winter the road into Camp Dick is not plowed, so the trail starts at the parking area where the Peak-to-Peak Highway (SR 72) crosses Middle St. Vrain Creek at Peaceful Valley, adding about a mile to the distance. There is another access point just east of the bridge at Peaceful Valley Campground. The mile-long stretch of Buchanan Pass Trail between the Camp Dick and Peaceful Valley campgrounds is a very pretty, short hike with lots of blue columbine in July.

Beaver Reservoir to Brainard Lake (7.4 miles, 800-foot elevation gain): This segment of the trail starts at the Sourdough Trail sign to your left just before you reach Beaver Reservoir, across the Beaver Reservoir Road from the previous section. The trail climbs through an area that burned in 1988. The stark, dead trees are now enveloped in a profusion of wildflowers in summer, and small aspen are thriving. When the aspen mature, this section should be a beautiful fall hike. In about 1 mile the trail forks at an old, unused road. There are no signs, but both branches later cross CR 96J and then rejoin in another 0.5 mile. The right branch (called the Sourdough Cutoff Trail) is shorter and used chiefly for cross-country skiing, but the left branch has more wildflowers. The proliferation of trails and old roads in this vicinity can be confusing, so keep an eye out for the blue diamonds used by the Forest Service for reassurance that you are on the main trail.

Beyond CR 96J, continue following the diamonds up through a mixed coniferous and aspen forest to a sign for the Baptiste-Wapiti Ski Trail, a loop maintained only for ski touring. At this point, the main trail makes a hairpin turn to the left and continues climbing until it levels out in a large meadow with views of the Indian Peaks. Twin ponds in the meadow are classic examples of the process of eutrophication: One pond is almost totally filled in with reeds, and the other (called Fresno or Dry Lake) has dried up to a fraction of its original size, as indicated by its shoreline. This stretch of the trail leads through aspen groves and is a colorful September hike.At frequent intervals, side trails, well-marked by the Forest Service, intersect the Sourdough Trail. Several of these trails go through private property with no public access and are so marked. Just beyond Fresno Lake, the Sourdough Trail branches. The left fork is a shorter route to the Red Rock Trailhead but is not presently maintained for hiking. The main Sourdough Trail continues up through a coniferous forest, eventually becoming steep enough to warrant a "Caution!" sign for bikers and skiers heading downhill.

After the steep section, the trail drops slightly to join the South St. Vrain Trail (which continues straight ahead about 3 miles to end at a small parking area above Brainard Lake). At this junction, turn left onto the combined Sourdough/South St. Vrain Trail and enjoy a fairly long downhill stretch paralleling the South St. Vrain Creek. Turn right (away from the south St. Vrain Trail) at the next junction, cross the bridge over the creek, and climb up to the Red Rock Trailhead below Red Rock Lake in the Brainard Lake Area. The road to the right leads to Brainard Lake.

Brainard Road to Rainbow Lakes Road (7.8 miles, 760-foot elevation loss): This segment of the Sourdough Trail begins 2.6 miles up Brainard Road, across the road from the Red Rock Trailhead, dropping to a bridge across Left Hand Creek. A grave marker for Brandon, "the most loyal dog that ever lived," is to the right. In about half a mile, the Little Raven Trail branches to the right. The Sourdough Trail contours around the lower flanks of Niwot Mountain, eventually crossing the Peace Memorial Bridge over Fourmile Creek. This stretch stays mostly in coniferous forest, mixed with some aspen. Occasionally, "windows" open up and offer views of the foothills and plains to the east, and of snowcapped peaks to the south. There are several small elevation gains and losses, but the trail more or less follows the 10,000-foot contour line until near the end when it drops fairly steeply to Rainbow Lakes Road (CR 116).

History

Camp Dick was a Civilian Conservation Corps (CCC) camp in the 1930s. CCC workers built 45 miles of trails in addition to building roads, dams, and fighting fires in the Indian Peaks area. In fact, the Sourdough Trail is (partly) a collection of some of these old roads.

Connections

The main connecting trails are Buchanan Pass Trail, South St. Vrain Trail, and Little Raven Trail. Laterals also connect with trails that lead into the Indian Peaks Wilderness.

Access

All the trailheads are west of the Peak-to-Peak Highway (SR 72). The four main access points are:

Camp Dick Campground on the Middle St. Vrain Road (5.8 miles north of Ward, 0.5 mile west of Peaceful Valley).

Sourdough Trailhead on the left-hand side of CR 96 just east of Beaver Reservoir (2.5 miles north of Ward, 2 miles west on CR 96).

Red Rock Trailhead on the right-hand side of CR 102 just east of Red Rock Lake (2.6 miles west on Brainard Lake Road).

Sourdough Trailhead on the right-hand side of Rainbow Lakes Road (CR 116, 4.7 miles south of Ward or 7 miles north of Nederland and 0.4 mile west on CR 116).